1. Field of the Invention
The present invention relates to an apparatus and method for generating dynamic picture images by effectuating polygon mapping using skeletons which are adaptable for use in advanced computer graphics architecture including but not limited to home-use television (TV) game machines. The invention also relates to storage or record media storing therein a software program for creation of such movable picture images for visual presentation on the screen of an associated display unit.
2. Description of the Related Art
Where an attempt is made to precisely represent movement or motions of a three-dimensional (3D) model structured from polygons, the resulting polygons increase in number causing workload of an associative central processing unit (CPU) to likewise increase when the CPU is designed to calculate endpoint coordinates on a mere step-by-step bases (vertex difference animation scheme), which in turn makes it difficult to move a model(s) on a real time basis. Especially, such prior known approach is not adaptable for use with TV games which are designed to allow more than one model to exhibit various kinds of motions or "actions" in rapid response to game player's operations of several types of key buttons of his or her game machine.
In recent years one scheme has been employed which utilizes multi-joint structures for enabling several kinds of actions to be by use of skeletons coupling between joint sections. This scheme using such multijoint structures will be briefly explained with reference to FIG. 26. In FIG. 26, a graphics image object 90 represents an animation character corresponding to a model of a human body, which object has a multijoint bone structure with a number of joints 91 at certain locations identical to those of real human joints. Adjacent ones of the joints 91 are coupled together by a corresponding one of bones 92 referred to as the "skeletons" in the art of computer graphics. Of those skeletons 92, one skeleton 92a coupled at one reference point A0 indicative of a joint 91 corresponding to the waist of human body is treated as a "parent" skeleton which is vectorically defined with such reference point A0 being as an origin. Further, its following skeletons 92 which are sequentially coupled from the parent skeleton 92a, head, both hands and both legs in this order are vectorically defined in a way such that one of them is defined by vector with an endpoint or tip of its upstream side one being as a reference. A surface of character 90 is three-dimensionally represented by a model which consists of a predefined number of polygons as defined in a way corresponding to respective skeletons 92. Where movement or motion is given to the model, respective skeletons 92 are sequentially supplied with vector data (what is called the "joint angle" data) in accordance with such intended motion causing a polygon associated with each skeleton 92 to be displayed while changing its position and/or angle in response to sequential movement of skeleton 92, which in turn leads to capability of visual presentation of the model's moving action. This scheme may be similarly applicable to cases of displaying animals as models in such a way that a modelled animal image is graphically defined for achievement of its motion as a multijoint structure having joints at locations corresponding to joints of a real animal.
The prior art multijoint structure based motion creation scheme with graphical joints being given to those joint locations of a real body offers capability of merely relatively simple actions of an animation character being displayed in operative corporation with angle data preset to skeletons, such as tilting and expansion/shrinking motions of its back, arms and legs--namely, partial bending and stretching actions--and also remains ineffective for providing more complicated actions to such character as presently displayed. Accordingly, applying to TV games such animation character with mere partial bending/stretching motion capabilities makes it impossible to accomplish a wide variety of character's complicated motions or actions as demanded by operators or "game players," which might disadvantageously serve as a serious bar to creation of idea-rich and enjoyable TV game software.